Method of and apparatus for opening metal sheets



Dec. 27, 1938. P. J. 'MURRAY 'ET Al. 2,141,218

METHOD OF AND APPARATUS FOR OPENING METAL SHEETS Filed Jan. '4, 1936 3noentors (Ittomeg Patented Dec. 27, 1938 METHOD OF AND APPARATUS FOR OPENING METAL SHEETS Peter J. Murray, Toronto, Ohio, and Erwin E. Bowen, Follansbee, W. Va.

Application January 4, 1936, Serial No. 57,462

20 Claims.

This invention relates to a method and apparatus for opening or separating stacks or piles of superimposed metal sheets such as black plate and particularly light gauge plate which have become adhered to each other during an annealing process.

In the manufacture of tin plate the sheets after rolling and shearing are arranged in piles and annealed in an annealing furnace, during which operation the sheets are subjected to a continued application of relatively high heat for a predetermined time. In the annealing furnace it is desirableto maintain thetemperature as high as possible to increasethe speed as well as the effectiveness of the annealing operation. Due to the weight of the superimposed sheets upon each other and the high temperature to which they are subjected, the sheets when removed from the furnace are often found to adhere closely to each other and must be separated after they have cooled and prior tofurther operations.

The common practice for separating the ad'- hered sheets is to lite-rally tear or pull the sheets I apart by manual labor which task is extremely arduous, calling for considerable man power and at the same time results in the mutilation of many sheets which become scrap. In many instances the piles of sheets must be pounded with heavy sledges in an attempt to effect preliminary rupture of the bond between the sheets before they can be separated. This operation which not only takes a considerable time also results in the mutilation of some of the sheets as well as being accompanied by some danger tothe workmen. In some instances, should the heat of the annealing furnace rise beyond a certain limit, especially when light gauge materials are being annealed, the sheets become so closely adhered to each other that manual separation is a practical impossibility.

In the methcd of opening piles of black plate with our invention, the deficiencies present in the prior inventions have been overcome. The apparatus is simple in construction and in. its method of operation and does not endanger the attending workmen. Packs of black plate maybe opened which heretofore could not be opened at a speed heretofore unprecedented. The ease of 5() operation and speed cut the cost of the opening operation materially. I

Still other advantages of the invention and the invention itself will become apparent from the following description of an embodiment thereof sawhich description is illustrated by the accompanying drawing and forms a part of this specification.

In the drawing:

Fig. 1 is an elevational view of the apparatus shown in operative position on a pile of black plate;

Fig. 2 is a sectional View through the apparatus of our invention and showing in dotted lines certain alternate positions which may be taken by certain moving parts;

Fig. 3 is a sectional View of a modified form of magnet for our apparatus.

The apparatus generally includes an electrically operated lifting magnet, the lifting face of which is hollowed or concave, together with an electric hammer operatively associated with the magnet to operate through the magnet.

It is to be understood that other types of hammering devices such as pneumatic, hydraulic, or mechanically operated hammers may be sub-' stituted for the electric hammer. We have found however, that an electric hammer operating on 25 cycles is particularly effective in operation.

Referring now particularly to the drawing throughout which like parts have been designated by like reference characters.

An electromagnet is provided and may comprise a pot or housing 2 of any desired conformation, that shown being round. and having a center pole 3 and an outer pole 4. Windings 5 are disposed in the housing surrounding the center pole and when energized cause a magneto flux to be set up in the manner well known in the art. This type of magnet has the greatest flux concentration at the center pole which is desirable as will later appear.

The face of the magnet may be hollowed out in the form of a concave cylindrical section; that shown in the drawing, however, being of substantially inverted V shape. The space opposite the windings surrounding the center pole is filled with a non-magnetic filler block 6, the surface of which conforms to the contour of the face of the magnet and the purpose of which is to provide a smooth uninterrupted face on the magnet which will not put undesired wrinkles or creases in the sheets.

It may be desirable to convert an existing magnet having a flat face to a magnet having the desired shape of lifting face and this may be effected as shown in Fig. 3 by providing an annular shoe 1 which is bolted or otherwise secured to the outer pole piece by studs 8 and which shoe tapers inwardly towards the center pole. A filler block 9, preferablyof non-magnetic material is disposed in back of the shoe to lend additional support therefor. It is to be noted that in Fig. 3 a concave face of a substantially spherical section has been shown; this may, however, be of cylindrical or inverted V section since we have found that the cylindrical or V. shaped face is particularly effective.

The top of the magnet housing is provided with the conventional sets of ears in disposed at equally spaced points from and about the center of the magnet. Secured on the ears I!) by pins -II are upwardly extending bars l2 which may be welded or otherwise secured to a head [3 at their upper extremities and which, together with the head, form a cage. The center pole of the magnet is provided with an axial bore l4 extending therethrough, and the head of the cage has an aperture l5 disposed in axial alignment with the bore M. The apparatus is adapted to be supported from a crane hook it by a coupling I! having an eye [8 through which the crane hook may extend. A rod It extends from the bottom of the coupling through the aperture Hand is provided at its lower end with cross head 26 adapted to engage the underside of the head l3. This arrangement provides a lost motion connection between the cross head and the cage for a purpose later described. The cross head 20 is provided with a guide whcih comprises a lateral extension 2| of the head having a notch 22' in its edge, the sides of which engage and are adapted to slide along one of the members l2. More than one of such guides may be provided if desirable.

Supported from the cross head 26 by rods 23 or otherwise connected to the head is an electric hammer 24. In some instances the cross head may be a part or integral with the hammer housing. The tool bar of the hammer extends downwardly through the bore [4 of'the magnet and is provided with a flat or round head 26 on its end which head may be renewable. The electric hammer has the usual piston or hammer disposed in a chamber and operable by a solenoid to impinge against the tool bar 25, when alternating current is applied, to transmit blows from the hammer through the tool bar 25 and head 26 to the article being hammered. I

When the magnet is lifted the lifting is effected from the crane through the coupling 11, rod I9, cross head 20, head I3, and the members 2, to the ears on the magnet housing. When the magnet is set down onto a stack of black plate the tool bar of the hammer, by means of the lost motion connection previously described, may be lowered a short distance through the bore M of the magnet, which distance is determined by the length of the rod H3. The rod I9 may reciprocate freely in the head I3, the limit of the reciprocation being the length of the rod [9 between the cross head and the coupling l1 and is sufficient to allow the hammer head to rest on'the top sheet. The coupling H is made heavy to provide additional weight for assisting the hammer bodily in its travel downward relative to the magnet.

The operation of the apparatus is substantially as follows:

As previously mentioned, the black plates 21 having been reduced to the desired thickness by rolling and shearing, are piled in stacks on a base 28. They are then covered by a hood and then the entire holder is placed in an annealing furnace where the temperature of. the black plate is brought up to the desired point and maintained for a predetermined certain length of time. Heretofore the peak temperature to which the black plate was subjected had to be kept within certain closely defined limits; insufficient heat failed to anneal the sheets properly and too much heat caused the sheets to adhere so closely that it was impossible to separate them after the annealing process was over. This limit, however, need not be so closely adhered to in view of our invention; in fact it can be raised about 200, sincewith this improved opening mechanism it is possible to open piles that previously defied opening. The black plate having been removed from the annealing furnace and allowed to cool, the piles are ready to be opened.

- The device, including the magnet and its appurtenances, are brought over the top of the pile by a suitable crane or the like, and the magnet 'is then lowered onto the top-most sheet of the pile. The concave face of the magnet itself. first contacts with the top of the pile; continued lowering of the crane hook it then permits the magnet to rest on the pile while the hammer 24 may be slid downward within the cage until the hammerhead 26 rests upon the top of the pile. The hammer is then energized by A. C. current and the electromagnet by D. 0. current. The fiux of the magnet causes the sheets to spring upwardly (Fig. 1) against the concave face of the magnet, which together with the hammering, effects separation of the superposed sheets adjacent the top of the pile. The number of sheets on top'of, the pile which are separated from the main body of the pile depends upon the flux of the magnet; the tendency of the sheets to adhere to each other; and the thickness of the sheets which are being separated. The position of the hammer relative to the magnet and to the sheets may also be regulated as desired by raising or lowering the crane hook. Under normal operation intermittent application of the current, both to the magnet and hammer, serves to loosen a considerable portion of the top sheets. When the top sheets have been separated or loosened,

the magnet may then be raised and the sheets removed. The magnet is then lowered onto the next group of unseparated sheets, and the process repeated. The application of current, both to the hammer and magnet, is not necessarily continuous, as we have found that by energizing and de-energizing both the magnet and the hammer intermittently most effective results are obtained.

In another method of application of the apparatus, the magnet is set on top of the sheets and the hammer is first actuated and the magnet subsequently energized after the hammer is withdrawn. We find, however, that separation is expedited, if both the hammer and magnet are energized simultaneously.

The effect of the magnet upon the sheets when brought into contact with the surface of the magnet by the flux of the magnet, may be likened to the riffling of a deck of cards. The fiux of the magnet being greatest at the center, the

attraction for the sheets is hence greatest at the center. The sheets are, therefore, flexed toward the face of the magnet and caused to assume the shape ofthe contour on the face of the magnet. This bending of the sheets causes the adjacent surfaces of the sheets to slide laterally relative to each other, rupturing the adhesion. It does not, however, bend the sheets sufiiciently to affect the sheets detrimentally, since they readily return to their normally flat position when the current is discontinued. I

In another method of operation the magnet and hammer are energized in contact with the sheets after which the magnet and hammer are deenergized and later elevated a short distance above the top-most sheets after which the magnet is again energized, causing the sheets to be attracted toward the magnet. In some instances it may be unnecessary to use the hammer, mere magnetic attraction and the shape of the surface of the magnet being sufiicient to afford the desired opening. It is obvious that the method of operation can varydepending upon the will of the operator and the particular character of the packs being opened.

As previously stated, the electric hammer may be replaced by other types of hammers, but for convenience and efliciency in operation we have found that the electric hammer is to be preferred. The concave surface of the magnet may also be varied as previously described to be of spherical instead of cylindrical section.

One method of operation that is particularly effective in the interestsv of increasing production is as follows: There are usually a number of piles of tin plate which are placed in a row. The operators start at one end of the row and, with a the mechanism of our invention, loosen the top sheets. of the first pile, after which they then shift the apparatus to the next pile and progress on down the row, loosening the top sheets on each pile. In the meantime the loosened sheets are removed from the piles first operated upon and they are now ready to have the unseparated sheets loosened. The apparatus having left the last pile is returned to the first and the cycle repeated. By this method there is no idle time for the magnet, nor for the portion of the crew which is removing the loosened sheets.

While the invention has been described in detail with specific examples, such examples are illustrative only and are not given as limitations since other modifications within the spirit and scope of the invention may be apparent to those skilled in the art.

We claim:

1. The method of opening piles of tin plate which comprises simultaneously magnetically bending and hammering the top portions of the pile.

2. The method of separating plates from a stack of adhering metal plates which consists in producing a magnetic field having a north pole and a south pole, positioning the center of the upper end of the stack within the field to attract the central area of those plates within the effective magnetic field toward one of the poles and out of the normal plane of the remaining plates of the stack, thereby flexing the attracted sheets to rupture the bond between the confronting surfaces of said plates, and simultaneously applying successive blows to the stack of plates to facilitate the separating action of the magnetic force.

3. The method of separating plates from a stack of adhering metal plates which consists in subjecting the stack of plates to a series of rapidly applied hammer blows and then producing a magnetic field having opposed poles, positioning the upper end of the stack within the magnetic field to attract a predetermined area of those plates within the eifective magnetic field toward one of the poles and out of the normal plane 00- cupied in stacked relation for flexing the attracted plates to rupture the bond between adjoining plates.

4. The method of separating plates from a stack of adhering metal plates which consists in subjecting the stack of plates to a plurality of rapid hammer blows, and producing a magnetic field having opposed poles, positioning the upper end of the stack within the magnetic field to attract a predetermined area of those plates within the effective magnetic field toward one of the poles and out of the normal plane of the remaining plates of the stack to flex the sheets for rupturing the bond between adjoining plates; then discontinuing the hammer blows and the production of the magnetic field to permit the disrupted plates to assume their substantial original positions; and. then producing a magnetic field at a predetermined distance more remote from said stack than the first production of magnetic force whereby the disrupted sheets are successively removed from the stack by the exerted magnetic force.

5. The method of separating plates from a stack of adhering metal plates which consists in subjecting the top-most portion of the stack of plates to a magnetic field to attract and flex those plates within the effective magnetic field out of the normal plane occupied by the nonaffected plates of the stack for rupturing the bond between the magnetically affected plates, and the auxiliary step of administering a series of 'violent hammer blows to the stack of plates to facilitate the separating action of the magnetic field.

6. The method of separating plates from a stack of adhering metal plates which consists in subjecting the top-most portion of the stack of plates to the elevating attraction of a magnetic field having its origin within close proximity to the surface of the top-most plate of the stack to attract and flex those plates within the effective range of the magnetic field out of the normal plane occupied by the remaining plates unaffected by the magnetic attraction for rupturing the bond between the magnetically affected plates; then discontinuing the magnetic attraction to permit said plates to assume their substantial original positions on the stack, and, finally, subjecting the stack to the elevating attraction of a magnetic field having its point of origin at a distance from the top-most plate more remote than the first mentioned magnetic field whereby the separated sheets are successively removed from the stack by the last mentioned magnetic force.

7. The method of separating plates from a stack of adhering metal plates which consists in simultaneously subjecting the topmost portion of the stack of sheets to repeated hammer blows and to the elevating attraction of a magnetic field having its origin above the surface of the topmost plate of the stack to attract and flex those plates within the effective range of the magnetic field out of the normal plane occupied by the remaining plates unafi'ected. by the magnetic attraction for rupturing the bond between the magnetically affected sheets for separating the latter.

8. In an apparatus of the class described, a magnet having a lifting face relieved in a zone toward its center, a bore through the magnet, a hammer supported above the magnet and having a tool extending through the magnet and adapted to be movable relative to the magnet.

9. The method of separating sheets from a pile of adhering sheets which consists in superposing an electromagnet over the topmost sheet of the pile, said electromagnet having a face of curved contour, jarring the pile of sheets to partially disrupt the adhesion between adjoining sheets, energizing the electromagnet to cause the sheets of the magnet when the lost motion connection is within the effective magnetic field to be flexed outwardly from the pile for further rupturing the adhesion between adjoining sheets, the magnetic force of said electromagnet individually attracting the uppermost sheets from the pile toward the face of the electromagnet where said sheets are retained until the eleotromagnet is de-energized.

10. In an apparatus for opening pilesof tin plate, an electromagnet including a center pole and an outer pole, the face of said magnet being of hollow cylindrical section, a support for the magnet including a cage connected to the magnet and a head on the end of the cage, a drawbar reciprocable through the head and having a crosshead on the end below the first mentioned head, an eye for the other end of the drawbar, a hammer connected to the crosshead and having a shank with a hammerhead on the end of the shank, said magnet having an axial bore extending through the center pole, said shank and hammerhead extending through and being reciproca'ble through said bore, said drawbar being reciprocable in said cage head to adjust the position of the shank and hammerhead in said bore.

11. In an apparatus of the class described, an electromagnet, a cage secured to the top of the magnet and having a head, a lost motion coupling for connecting and supporting the magnet, including a connector for attachment to a crane, and a rod extending from the end of the connector through said head and having a cross head 7 on the end disposed within said cage, a hammer connected to said cross head and having a ham- 1 merhead adapted to be moved beyond the confines of the magnet.

12. Inan apparatus of the class described, an electromagnet having a center pole and a concentric outer pole, the lifting face of the'magnet being hollowed out in the form of a segment of a cylinder, a bore extending axially through the center pole, bars secured to the top of the magnet and having their ends connected to a head, said head being formed to provide a centrally disposed aperture in alignment with the bore in the center-pole, a lost motion coupling for connecting and supporting the magnet, including an eye member having an eye in one end for the reception of a crane hook or the like, a rod extending from the end of the eye adapted to be positioned through the aperture in said head, a cross head on the end of said rod disposed on the opposite side of said first mentioned head from the eye, a guide extending laterally from the cross head andadapted to engage one of said bars, an electric hammer connected to said cross head and having a shank with a hammerhead on the end thereof and extending into the bore of said center pole, said hammerhead adapted to be moved beyond the confines of the bore moved relative to the magnet.

13. In a device for opening piles of black plate, an electromagnet including a housing, a center pole provided with a bore, and a concentrically disposed outer pole, the face of the magnet being of concave formation, a hammer for the magnet suspended above the magnet and adapted to have a tool lowered and operable through the bore of the magnet.

14. The method of separating plates from a pile of adhering metal plates which consists in placing an electromagnet in contact with the upper plate of the pile, energizing the electromagnet in a manner to cause the plates within the effective magnetic field to flex outwardly of the pile at the center thereof whereby the edge portions of said plates are caused to move inwardly along the face of adjacent plates.

15. The method of separating a plate from a pile of adhering metal plates which consists in producing a magnetic field having a north pole and a south pole, and positioning the center of one end of the pile closely adjacent one pole of said field in a manner to attract a central area of the outer sheet away from the adjacent sheet and thereby cause the. edge portions of the outer sheet to be moved inwardly along the face of the adjacent sheet.

16. The method recited in claim 15 and the additional step of applying successive blows to the pile of plates to initially disrupt the adhesion between adjoining sheets.

17. The method of separating plates from a pile of adhering metal plates which consists in positioning one end of the pile adjacent to an electromagnet, energizing the magnet, restraining the outer portions of the outermost plates from movement toward the magnet, but permitting the central portion of said plates to flex towards the magnet tov tear the sheets within the magnetic field away from the pile.

18. The method recited in claim 17 and the additional step of de-energizing the electromagnet to permit the disrupted sheets to assume their original position as a body, then re-energizing the electromagnet whereby the several outermost loosened sheets are flexed centrally and withdrawn in succession from the pile.

19. In an apparatus of the class described, an electromagnet including a center pole and an outer pole surrounding the center pole, said center pole being provided with an axial bore, a support for the magnet comprising bars connected to the magnet and an apertured head connected to the bars, a coupling for connection to a crane hook or the like, a rod extending from the coupling through the aperture in the head and having a crosshead secured to the rod below said first mentioned head, said coupling rod and crosshead being capable of limited longitudinal movement relative to the magnet, and a hammer suspended from the crosshead and having a tool and hammerhead extending into the bore of the center pole and adapted to be moved through the magnet upon the relative movement of said crosshead.

20. In an apparatus of the class described, an electromagnet having a center pole and a concentric outer pole, the lifting face of the magnet being hollowed out to provide portions of the peripherydisposed in a plane below the center pole, a bore extending axially through the center pole, a cage secured to the top of the magnet and having a head, a lost motion coupling for connecting and supporting the magnet, including a connector for attachment to a crane, a rod ex tending from the end of the connector through said head and having ,a crosshead on the end disposed within said cage, and a hammer connected to said crosshead and having a hammerhead adapted to be lowered beyond the confines of the bore of the magnet when the lost motion connection is moved relative to the magnet.

PETER J. MURRAY. ERWIN E. BOWEN. 

